Steam generator



Jan, 24, 1939. D. K. WRIGHT 2,145,104

STEAM GENERATOR Filed Aug. 29, 1936 Inventor: Danie? l4. Wright,

6 M50444 by At ijorney pig, l,

Patented Jan. 24, 1939 PATENT OFFICE STEAM GENERATOR Daniel K. Wright, Cleveland Heights, Ohio, assignor to General Electric Company, a corporation of New York Application August 29, 1936, Serial No. 98,513

11 Claims.

My invention relates to electric water heaters and steam generators in which both the electric heating element and. the boiler are located in an, inert environment. My invention relates par- 5 ticularly to a specific generator in which the boiler is located in a vitreous casing and the heating unit therefor is comprised of a filamentary electric resistance wire, and to a method of making said generator.

Steam generators of this type constructed previous to this invention were not satisfactory because of their high cost, their uncertain life and their inability to Withstand rough treatment. To reduce the cost I substitute, for the relatively expensive vitreous and bulbous casing in which the elements of the generator are located, a casing formed from two duplicate and inexpensive end assemblies and a simple tubular middle section. To increase the certainty of long life and ruggedness, I provide means for holding all portions of the filamentary heating element securely in position and additional means for supporting said holding means at both ends of the generator. In certain prior constructions, the filamentary heating element, when changing temperature, tended to squirm out of position and being located very near the boiler, often touched it rendering the generator inoperative. Other features and advantages of my invention will be apparent from the detailed description which follows of one species thereof and from the accompanying drawing.

In the drawing, Figs. 1, 2 and 3 are side elevations of three steps in the manufacture of the steam generator of my invention; Fig. 4 is a perspective view of a portion of the electrical heating means therefor and. Fig. 5 is a side elevation of the complete steam generator of my invention.

40 According to my invention, the first step in the manufacture of my steam generator consists in the fusing of the end assembly I!) to the vitreous tube I I. The end assembly I corresponds to the cup portion of the electric lamp shown. in my United States Patent 1,967,852, issued July 24, 1934, and is comprised of the vitreous cup I2 and. the metal open-ended thimbles I3 and I 4. The cup I 2 is provided with the tubulations I and 96 which are sealed to vitreous rings H which in t turn are sealed to both sides of the thin tapering edges I8 of the thimbles I3 and I4 as disclosed in my Patent 1,967,852 hereinbefore referred to. The thimbles I3 and I 4 are preferably made of copper and provide a seal of the type shown in Kruh and Wolf Patent 1,564,680, issued December 8, 1925, and Houskeeper Patent 1,294,466, issued February 18, 1919. A well I9 is provided in the cup III for purposes of supporting the interior parts of the generator. Only the edges of the vitreous cup I2 and the vitreous tube I I are heated by pin point flames (not shown) and the parts are fused together without distortion, as shown in Fig. 2.

The second step in the manufacture of my steam generator, as shown in Fig. 2, consists in the inserting of the inlet and outlet tubes 2!! and M of the boiler 23 through the open ends of the thimbles I3 and I4 respectively, and the brazing of said tubes and 2! thereto. The material, silver solder in this case, with which the thimbles I3 and I4 and the tubes 20 and 2| are brazed to gether, seals off the openings in said thimbles completely so that the end of the generator shown is hermetically sealed. The inlet pipe 20 passes between the tubing II and the boiler 23, and is flattened slightly so as not to touch the inner wall of the tubing I I. The boiler 23 and the inlet and outlet tubes 20 and 2| in this instance are developed from a single piece of copper tubing which is coiled and brazed together to form the boiler 23.

The third manufacturing step consists in the construction of the heating unit 24 (Fig. 3) on the second end assembly 25. The heating unit 24 consists of the coiled tungsten filament 2B which is connected indirectly to the closed-ended thimbles 21 and 28 and the supporting structure 29 therefor which is mounted on the thimble 21. The thimbles 21 and 28 are provided with thin edges which are sealed to the tubulat-ions 30 and 3| extending fromthe vitreous cup 32 and function as terminal elements for the steam generator. The coiled filament 25 is draped in a second helix about the supporting structure 29 there-for which engages the filament 26 at 120 intervals through the support wires 33. Each of the support wires 33 is bent down between the coils of the filament 26 so as to prevent any longitudinal movement thereof and is threaded up and down through two holes in an insulating block 34. The insulating blocks 34 are molded from a product manufac tured by the Champion Spark Plug Company, called Sillimanite and are mounted one upon the other on the arbor 35. The blocks 34 have an irregularly shaped hole therein which engages the three equidistantly located fiats on the arbor 35 and are prevented from turning out of position thereby. The ends of the filament 25 are uncoiled and are completely covered by closely fitting wire coils 36 which are, together with the filament 26, attached to the arbor 35 and the post 3? respectively. The arbor 35 is supported by the thimble 21 through the arm 38 and the post 39 whereas the post 37 is attached directly to the thimble 28. The arbor 35 passes through an aperture in the arm 38 and is welded thereto. The posts 31 and 39 pass into the thimbles 28 and 21 respectively and-are preferably welded thereto. The filament 26 is held in the correct'position on the arbor 35 by the end thereof which is welded to said arbor and by the washers 4, 4| and 42 which separate arm 38 and the lowermost block 34. For purposes of holding the boiler 23 in position after complete assembly, a separator 43 is provided which is mounted ,ina groove in insulating washer 4|. The separator 43 has three legs which engage the inside walls of the boiler 23 and is held in one position, so as not to contact the end of the filament 26, by the wire 44. The wire 44 is welded to the separator 43 and is threaded back and forth through two holes in the insulating block 45 which is connected to the arm 38 through the wire 46 which is also threaded back and forth through two holes in said block. An exhaust tube 41 is fused to the vitreous cup 32 as shown.

The next stepin the manufacture of my steam generator consists in placing the boiler 23 and the vitreous tube II over the heating unit 24, in fusing the tube H and cup 32 together, in exhausting and filling said generator with an inert gas. When the boiler 23 is passed over the heating unit 24, the cap 48 on the end of the arbor 35 is introduced into the well IQ of the cup In so as to give support to the free end of the heating unit. Once the vitreous tube II is fused to the cup 32, the casing about the boiler 23 and heating assembly is complete and the exhausting and gas filling operations are carried on through the exhaust tube 41. After these operations the generator is completed by tipping off the exhaust tube 41 as shown.

What'I claim as newand desire to secure by Letters Patent of the United States is:

1. The method of manufacturing a steam generator, which comprises an end assembly including a vitreous cup and a boiler mounted thereon, a second end assembly including a second cup and a heating unit mounted thereon, and a vitreous tube, which consists in inserting said end assemblies into opposite ends of the vitreous tube to position the boiler and heating unit in operative relation to each other, fusing said vitreous cups to the ends of the vitreous tube to seal the boiler and heating unit in a vitreous casing and exhausting the casing to remove the gases having a deleterious effect on the heating unit.

2. The method of manufacturing a steam generator, which comprises an end assembly'including a vitreous cup with open-ended thimbles sealed thereto, a boiler having inlet and outlet tubes, a second end assembly including a second cup and a heating unit mounted thereon, and a vitreous tube, which consists in inserting the inlet and outlet tubes of the boiler into the open ends of respective thimbles and brazing said tubes thereto to close off the openings therein, inserting said end assemblies into opposite ends of the vitreous tube to position the boiler and heating unit in operative relation to each other, fusing said vitreous cups to the ends of the vitreous tube to seal the boiler and heating unit in a vitreous casing and exhausting the casing to remove the gases having a deleterious effect on the heating unit.

3. The method of manufacturing a steam generator, which comprises an end assembly including a vitreous cup and a boiler mounted thereon, a second end assembly including a second cup with metal thimbles sealed thereto, a heating unit including a filament, and a vitreous tube, which consists in mounting the heating unit on the metal thimbles of the second vitreous cup, connecting the ends of the filament to respective thimbles, inserting said end assemblies into opposite ends of the vitreous tube to position the boiler and heating unit in operative relation to each other, fusing said vitreous cups to the ends of the vitreous tube to seal the boiler and heating unit in a vitreous casing and exhausting the casing to remove the gases having a deleterious effect on the heating unit.

4. The method of manufacturing a steam generator, which comprises an end assembly includ ing a vitreous cup with open-ended thimbles sealed thereto, a boiler having inlet and outlet tubes, a second end assembly including a second cup with metal thimbles sealed thereto, a heating unit including a filament, and avitreous tube, which consists in inserting the inlet and outlet tubes of the boiler into the open ends of the .respective thimbles of the first'vitreous cup, brazing said tubes thereto to close off the openings therein, mounting the heating unit on themetal thimbles of the second vitreous cup, connecting the ends of the filament to respective thimbles, inserting said end assemblies into opposite ends of the vitreous tube to position the boiler and heating unit in operative relation to each other, fusing said vitreous cups to the ends of the vitreous tube to seal the boiler and heating unit in a vitreous casing and exhausting the casing to remove the gases having a deleterious effect on the heating unit.

5. An electric steam generator comprising a boiler having inlet and outlet tubes, an electric heating unit having a filament within said boiler, a vitreous casing enclosing said boiler and said heating unit having pairs of tubulations at opposite ends thereof, a pair of open-ended metal thimbles sealed to the tubulations at one end of said casing and having the inlet and outlet tubes 7 of said boiler passing therethrough and hermetically sealed thereto and a second pair of out wardly extending metal thimbles sealed to the tubulations at the opposite end of the casing, said heating unit being supported directly by saidlastnamed pair of thimbles and said filament being electrically connected at its ends to said thimbles.

6. An electric steam generator comprising a boiler having inlet and outlet tubes, an electric heating unit having a filament within said boiler, a vitreous casing enclosing said boiler and said heating'unit having a well at one end adapted to engage and support one end of the heating unit and having pairs of tubulations at opposite ends thereof, a pair of open-ended thimbles sealed to the tubulations at the end of said casing containing the well and having the inlet and outlet tubes of said boiler passing therethrough and hermetically sealed thereto and a second pair of outwardly extending metal thimbles sealed to the tubulations at the opposite end of the casing, said heating unit being supported at its end opposite said well directly by said last-named pair of thimbles and said filament being electrically connected to said thimbles.

7. An electric steam generator comprising a boiler having inlet and outlet tubes, an electric heating unit within the'boiler having a centrally disposed arbor, a filament coiled around said arbor having one end attached thereto, means fastened to the filament in intervals and engaging the arbor for holding said filament in place, a vitreous casing enclosing said boiler and said heating unit having a pair of tubulations at opposite ends thereof, a pair of open-ended thimbles sealed to the tubulations at one end of said casing and having the inlet and outlet tubes of said boiler passing therethrough and brazed thereto .1 and a second pair of thimbles sealed to the tubulations at the opposite end of the casing, means attached to one of said second pair of thimbles for supporting one end of the arbor and means attached to the other of said second pair of thimbles and to the second end of the filament for completing the circuit from said thimbles to the filament.

8. An electric steam generator comprising a boiler having inlet and outlet tubes, an electric heating unit within the boiler having a centrally disposed arbor of non-circular cross-section, a filament coiled around said arbor having one end attached thereto, support wires fastened to the filament at intervals, insulating blocks apertured for the arbor and mounted one upon the other thereon and attached to said support wires for holding the filament in place, means supported by the arbor and engaging the boiler for locating the heating unit therein, a vitreous casing enclosing the said boiler and the said heating unit having a well at one end adapted to receive one end of the arbor to hold it in place and having a pair of tubulations at opposite ends thereof, a pair of open-ended thimbles sealed to the tubulations at the end of said casing containing the well and having inlet and outlet tubes of said boiler passing therethrough and brazed thereto and a second pair of thimbles sealed to the tubulations at the opposite end of the casing, means attached to one of said second pair of thimbles for supporting the other end of the arbor and means attached to the other of said second pair of thimbles and to the second end of the filament for completing the circuit from said thimbles to the filament.

9. An electric steam generator comprising a vitreous casing consisting of a tubular portion having separate cup-shaped end portions hermetically fused to the ends thereof, each of said cupshaped portions having a pair of openings in the ends thereof, a boiler disposed in said casing and having inlet and outlet tubes extending through the openings in one of said end portions, means hermetically sealing said outlet and inlet tubes to the walls of said openings, a pair of outwardly extending rigid metal terminal members sealed to the walls of the openings in the opposite end portion of the casing, a heater consisting of a filament mounted within said boiler, and means for supporting said filament, said filament being electrically connected at its ends to said terminal members.

10. An electric steam generator comprising a vitreous casing consisting of a tubular portion having separate cup-shaped end portions hermetically fused to the ends thereof, each of said cup-shaped portions having a pair of openings in the ends thereof, a boiler disposed in said casing and having inlet and outlet tubes extending through the openings in one of said end portions, means hermetically sealing said outlet and inlet tubes to the Walls of said openings, a pair of out wardly extending metal terminal members sealed to the walls of the openings in the opposite end portion of the casing, a heater consisting of a filament mounted within said boiler, and means for supporting said filament comprising an arbor extending longitudinally of said casing, said arbor being supported at one end directly from one of said terminal members, said filament being electrically connected at its ends to said terminal members.

11. An electric steam generator comprising a vitreous casing consisting of a tubular portion having cup-shaped end portions hermetically sealed to the ends thereof, each of said cupshaped portions having a pair of openings in the ends thereof, a boiler disposed in said casing and having inlet and outlet tubes extending through the openings in one of said end portions, means hermetically sealing said outlet and inlet tubes to the walls of said openings, a pair of metal terminal members sealed to the walls of the openings in the opposite end portion of the casing, a heater consisting of a filament mounted within said boiler, and means for supporting said filament comprising an arbor extending longitudinally of said casing, said arbor being supported at one end directly from one of said terminal members, the opposite end of said arbor being centered in a well in the casing end portion through which the said inlet and outlet tubes extend, said filament being electrically connected at its ends to said terminal members.

DANIEL K. WRIGHT.

CERTIFICATE OF CORRECTION. Patent No, 2,1Lq.5,l0l4.. January 21.1,, 1959.,

o DANIEL K. WRICIHTa It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 5, second column, line 20, claim 10, before the word "metal" insert rigid; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 21st da; of March, A. D. 1959.

Henry Van arsdaleo (Seal) Acting Commissioner of Patents CERTIFICATE OF CORRECTION. Patent No. 2,1L .5,l0h. January 2h, 1959.,

, DANIEL K. WRIGHT It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows; Page 5, second column, line 20, claim 10, before the word "metal" insert rigid; and that the said Letters Patent shouldbe read with this correction therein that the same may conform to the record of the case in the Patent Office Signed and sealed this 21st day of March, A. D. 1959.

Henry Van Arsdale.

(Seal) Acting Commissioner of Patents. 

